Research: Mary Lou Guerinot studies the molecular mechanisms of metal ion uptake and its regulation in both prokaryotic and eukaryotic cells. She uses a combined genetic, molecular and biochemical approach to examine the uptake of iron, zinc, manganese and cadmium in the yeast Saccharomyces cerevisiae and the model plant Arabidopsis thaliana. Her goal is to ultimately understand the functional connections between genes, proteins, metabolites and mineral ions. As part of a multi-investigator project, Guerinot is using ICP-MS [inductively coupled spectroscopy-mass spectroscopy] nutrient and trace element profiling as a tool to determine the biological significance of connections between a plant's genome and its elemental profile. They are screening loss of function mutants in each of the predicted ORFs in the Arabidopsis genome and have already identified a number of proteins of unknown function that dramatically alter a plant's elemental composition. The lab is also investigating the reduction of iron by a family of membrane-bound Fe(III) reductases and metal metabolism in the symbiosis between Bradyrhizobium japonicum and soybeans.